EMI Bites: Missing Return Planes Jeopardize PCB Compliance
EMI Bites: Missing Return Planes Jeopardize PCB Compliance
You've spent months carefully designing your PCB, expecting smooth certification testing, only to hit the wall of EMI test failures that can derail your entire project.
The hidden problem?
Forgetting to include a Return Reference Plane (RRP) for your signal layers.
Why does this oversight cause such big problems?
- Fields escape your board: Without an RRP underneath, electrical fields from your signals leak out beyond the PCB edges, broadcasting interference to nearby electronics.
- Certification failures: These uncontrolled emissions violate EMC standards, causing your product to fail compliance testing.
- Expensive fixes: Solving EMI problems after production means costly redesigns, new prototypes, and major delays to your project timeline.
Here's the key insight:
Signals need a stable return path to stay contained—without it, your board becomes an EMI generator!
My go-to fixes for robust, EMI-compliant designs:
- Include a dedicated RRP layer beneath signal traces
- Ensure the RRP is solid and continuous
- Route signals over the RRP to confine fields
- Resolve EMI issues during the layout phase
—Dario
P.S. Want more EMI control strategies to pass EMC?